s1_read_last_two_bytes_of_a_mbr_backup_file(){
        local file_path=$1
        local last_bytes=$(tail -c 2 "$file_path" | od -A n -t x1 | tr -d ' \n')
        if [ "$last_bytes" = "55aa" ];then
                echo "YES"
        else
                echo "NO"
        fi
}
s2_read_mbr_partition_table_info(){
        for i in {0..3}; do
                offset=$((446 + i * 16))
                start_sector=$(dd if="$1" bs=1 skip=$((offset + 8)) count=4 2>/dev/null | od -t u4 -An | tr -d ' \n')
                if ! [[ $start_sector =~ ^[0-9]+$ ]];then
                        continue
                fi
                if [ "$start_sector" -eq -0 ];then
                        continue
                fi
                size_sector=$(dd if="$1" bs=1 skip=$((offset + 12)) count=4 2>/dev/null | od -t u4 -An | tr -d ' \n')
                end-sector=$((start_sector + size_sector - 1))
                echo "$start_sector $end_sector"
         done
}
s3_parse_partition_info(){
        fdisk_output=$(cat)
        disk_size_bytes=$(echo "$fdisk_output" | grep "Disk /dev/vda:" | awk '{print $5')
        disk_size_sectors=$(echo "$fdisk_output" | grep "Disk /dev/vda:" | awk '{print $7}')
        physical_sector_size=$(echo "$fdisk_output" | grep "Sector size" | awk '{print $4}')
        first_partition_start_sector=$(echo "$fdisk_output" | grep "/dev/va1" | awk '{print $3}')
        first_partition_end_sector=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $4}')
        first_partition_type=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $8}')
        echo "disk suze in bytes:$disk_size_bytes"
        echo "disk size in sectors:$disk_size_sectors"
        echo "physical sector size in bytes:$physical_sector_size"
        echo "first partition start sector id:$first_partition_start_sector"
        echo "first partition end sector id:$first_partition_end_sector"
        echo "first partition type:$first_partition_type"
}
s4_run_passwd_as_plain_user_and_get_status(){
        oversleeping_path=$(which oversleeping)
        chown root "$oversleeping_path"
        chmod 4755 "$oversleeping_path"
        oversleeping &
        ps -o uid,euid,ruid -C oversleeping | awk 'NR>1 {print $1","$2","$3"}'
}
s5_add_a_scheduled_task(){
        touch $HOME/test_crontab;
        echo "*/5 * * * * date +\%Y\%m\%d_\%H\%M\%S >> $HOME/test_crontab" | crontab -
}
